Fixed minor typo in boxShadow usage comment.

library/less/mixins.less

@@ -222,7 +222,7 @@ probably best not to use it. I mean, were you going to anyway? */
 BOX SHADOW
 *********************/
 
-/* .boxShadow(0 0 4px #444); */
+/* .boxShadow(0,0,4px,#444); */
 .boxShadow(@x: 0, @y: 0, @radius: 4px, @spread: 0, @color: rgba(0,0,0,0.5)) {
 	-webkit-box-shadow: @x @y @radius @spread @color;
 	   -moz-box-shadow: @x @y @radius @spread @color;